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DOI: 10.1055/s-2008-1042732
ortho-Selective Cross-Coupling of Dichlorobenzenes with Grignard Reagents
Contributor(s):Paul Knochel, Andrei GavryushinRIKEN, Wako, Japan
Highly Ortho-Selective Cross-Coupling of Dichlorobenzene Derivatives with Grignard Reagents
Org. Lett. 2007, 9: 5593-5595
Publication History
Publication Date:
21 February 2008 (online)
Key words
dichlorobenzenes - cross-coupling - ortho selectivity
Significance
The problem of the regioselectivity in cross-coupling reactions of functionalized dihaloarenes is important from the practical point of view. In this publication, the authors demonstrated highly ortho-selective coupling reactions of dichlorinated phenols, anilines and their derivatives, bearing an anionic coordinating group. Aryl, hetaryl, and alkenylmagnesium halides are suitable coupling partners. Using a specially designed ligand 1, o-chlorine can be coupled preferentially in the presence of a bromine atom in another position.
Comment
Many examples of regioselective cross-coupling of dihaloheteroarenes are known (see review below). Ishikawa and Manabe also recently reported the ortho-selective coupling of dibromophenols and dibromoanilines, using the terphenyl ligand 1 (see scheme; Chem. Lett. 2007, 36, 1304). A similar reaction with arylboronic acids as nucleophiles failed to give any significant regioselectivity.
Review
S. Schröter, C. Stock, T. Bach Tetrahedron 2005, 61, 2245.